The present invention relates to a reducing agent containing at least two components, comprising a solid composition in powder form and a liquid composition, which are intended to be used in a process for treating keratin substances, in particular the hair, in order to permanently reshape the hair, and to processes using this agent.
One of the techniques commonly used in cosmetics to imprint a long-lasting shape on the hair consists in reshaping the hair by using a reducing agent and then an oxidizing agent.
The technique most commonly used for permanently reshaping the hair consists, in a first stage, in opening the Sxe2x80x94Sxe2x80x94 disulphide linkages in keratin (cystine) using a composition containing a reducing agent, and then, after the hair thus treated has been rinsed, in reconstituting the said disulphide linkages, in a second stage, by applying to the hair, which has been placed under tension beforehand by means of rollers or the like, or else placed in shape or smoothed out by other means, an oxidizing composition also known as a xe2x80x9cfixerxe2x80x9d, so as finally to give the hair the desired shape.
This technique thus makes it possible either to make the hair wavy or to straighten it out or remove its curls, or alternatively to make it smooth.
This new shape given to the hair by a chemical treatment is long-lasting over time for a few weeks and especially withstands the action of washing with water or with shampoos, compared with techniques using styling products which lead to temporary reshaping, such as hair setting, this reshaping disappearing, however, on styling or washing with shampoo.
The reducing compositions generally used for the first step of a permanent-waving operation contain, as reducing agents, sulphites, bisulphites or, preferably, thiols. Among these, mention may be made more particularly of cysteine and its derivatives, cysteamine and its derivatives, thiolactic acid, thioglycolic acid and its esters, in particular glyceryl thioglycolate. Thioglycolic acid is particularly effective and constitutes the product most commonly used for reducing the disulphite linkages of keratin.
However, it is observed that, on account of the reducing properties of these components, compositions containing reducing agents have the drawback of having poor stability in solution. For many reducing agents, white deposits are especially found in the bottom of the containers containing the reducing compositions, and the development of an unpleasant odour of hydrogen sulphide is also noted.
These changes are accompanied by a reduction in the titre of reducing agents and thus of their efficacy.
It is particularly difficult to fragrance reducing media on account of the considerable degradation, during storage, of the fragrances by these reducing agents.
The present invention solves these problems by providing a two-component reducing agent comprising a first component consisting of a solid composition in powder form containing a keratin-reducing agent, and a second component consisting of a liquid without keratin-reducing agent. The reducing composition is prepared at the time of use by mixing together the compositions just immediately before applying the mixture to the keratin fibres.
One subject of the invention thus consists of a reducing agent containing at least two components, comprising a composition in powder form containing a reducing agent.
Another subject of the invention consists of a process for permanently reshaping the hair, using a reducing agent resulting from the use of a composition in powder form mixed with a liquid at the time of use.
Other subjects of the invention will become apparent on reading the description and the examples which follow.
The solid composition in powder form in the reducing agent in accordance with the invention is essentially characterized in that it comprises at least one keratin-reducing agent in solid form or adsorbed onto a solid.
Examples of solid reducing agents which can be used according to the invention are sulphites, cysteine, cysteamine or one of their cosmetically acceptable salts such as the hydrochlorides, hydrobromides, citrates, acetates or sulphates.
Among the reducing agents which can be adsorbed onto powders, mention may be made, for example, of thioglycolic acid, thiolactic acid or their salts, thioglycolic acid esters such as glyceryl thioglycolate, or thiolactic acid esters.
The solids which can be used as adsorption supports are, for example, silicas, clays, carbohydrates such as starches, or organic polymers such as Nylon.
The reducing compound is used in proportions such that, in the reducing composition at the time of use, it is present in amounts that are sufficient to reduce the xe2x80x94Sxe2x80x94Sxe2x80x94 linkages, and preferably between 1 and 25%, in particular from 3 to 25%, by weight.
The composition preferably contains thickeners in powder form and preferably thickeners derived from natural substances such as, more particularly, guar gum, tara gum, spruce meal or synthetic thickeners such as acrylic or methacrylic acid polymers, for instance methacrylic acid/methyl methacrylate copolymer such as the product sold under the name Rohagit HSV (methacrylic acid/methyl methacrylate (33/67) non-crosslinked copolymer).
The composition can also contain other additives usually used in reducing compositions and which do not interfere with the reducing properties of the composition, such as polymers in powder form, and basifying or acidifying agents in powder form such as, more particularly, arginine or citric acid.
In the context of the process in accordance with the invention, this composition in powder form is used together with the liquid composition without keratin-reducing agent containing, in an aqueous medium consisting of water or a water/cosmetically acceptable solvent mixture, adjuvants usually used in reducing compositions.
The pH of the liquid compositions is adjusted so as to give the ready-to-use reducing composition a pH generally of between 6.5 and 11.5.
The alkaline agents can be chosen from monoethanolamine, diethanolamine, triethanolamine, isopropanolamine, 2-methyl-2-amino-1-propanol, 1,3-propanediamine, an ammonium or alkali metal carbonate or bicarbonate, an organic carbonate such as guanidine carbonate, or an alkali metal hydroxide, which are used alone or as a mixture.
The reducing agent can also contain, either in the powder part, in the liquid part or in the final powder-liquid mixture, surfactants or treating agents of anionic, nonionic, amphoteric or cationic nature.
The surfactants used can be of nonionic, anionic, cationic or amphoteric type, which are commonly used in permanent-wave reducing compositions. Among these, mention may be made of alkyl sulphates, alkyl benzenesulphates, alkyl ether sulphates, alkyl sulphonates, quaternary ammonium salts, alkylbetaines, oxyethylenated alkylphenols, fatty acid alkanolamides, oxyethylenated fatty acid esters and nonionic surfactants of the hydroxypropyl ether family.
These surfactants are generally used in proportions such that, in the composition resulting from the mixture of the powder and the liquid, their maximum proportion is about 30% by weight, and preferably between 0.5 and 10% by weight, relative to the total weight of the composition.
Treating agents which may be used are volatile or non-volatile, linear or cyclic silicones or mixtures thereof, polydimethylsiloxanes, quaternized polyorganosiloxanes, those described in French patent application 2 535 730, polyorganosiloxanes containing an aminoalkyl group which are modified with alkoxycarbonylalkyl groups, as described in patent U.S. Pat. No. 4,749,732, polyorganosiloxanes such as polydimethylsiloxane-polyoxyalkyl copolymers such as dimethicone copolyol, a polydimethylsiloxane containing stearoxy-(stearoxydimethicone) end groups, a polydimethylsiloxane dialkylammonium acetate copolymer or a polydimethylsiloxane polyalkylbetaine copolymer described in GB-A-2 197 352, polysiloxanes organomodified with mercapto or mercaptoalkyl groups as described in FR-B-1 530 369 and EP-A-0 295 780, as well as silanes such as stearoxytrimethylsilane.
It is also possible to use other treating ingredients, such as waxes, polymers chosen from cosmetically acceptable polymers which can be, cationic, anionic, nonionic or amphoteric polymers, swelling agents and penetrating agents for reinforcing the efficacy of the reducing agent, such as dimethylisosorbitol, urea and its derivatives, pyrrolidone, n-alkylpyrrolidones, thiamorpholinone, alkyl ethers of alkylene glycol or of dialkylene glycol, such as, for example, propylene glycol monomethyl ether, dipropylene glycol monomethyl ether, C3-C6 alkanediols such as, for example, 1,2-propanediol, 2-imidazolidinone, as well as other compounds such as fatty alcohols, lanolin derivatives, ceramides, in particular ceramides themselves, the glycoceramides and the pseudoceramides described in particular in FR-A-95/1399, and in DOWNING Journal of Lipid Research, Vol. 35, p. 2060, 1994, or in FR-A-2 673 179, EP-A-0 227 994, WO-94/07844 or WO-92/05764, whose contents are included by reference, active ingredients such as pantothenic acid, agents for preventing hair loss, antidandruff agents, suspending agents, sequestering agents, opacifiers, colorants and sunscreens, as well as fragrances and preserving agents.
At the time of use, the powder containing the keratin-reducing agent is mixed with the liquid composition without keratin-reducing agent. The ratio of the mixture is between 0.01 and 4 by weight, i.e. from 1 to 80% by weight, relative to the total weight of the final composition, of the composition in powder form and from 99% to 20% of the composition in liquid form can be used.
The process in accordance with the invention is carried out by mixing, as indicated above, the composition in powder form containing the reducing agent with the liquid composition in the proportions indicated above. The resulting composition after mixing is applied to hair which has preferably been moistened beforehand.
This application can be carried out before, during or after the optional step of placing the hair under tension in a shape corresponding to the desired final shape for this hair, such as curls.
When thickeners are used with the powder, the process can optionally be carried out without placing the hair under tension, but instead by simply applying the composition using the fingers or a comb, thus allowing the hair to be sculpted and to be held in a desired position such as curls, waves or spikes.
According to an optional step of the process of the invention, after applying the reducing composition, the hair can be subjected to a heat treatment by heating to a temperature of between 30 and 60xc2x0 C. This heating optionally allows the final degree of curliness of the hair to be adjusted.
In practice, this operation can be carried out using a hairdrying hood, a hair dryer, an infrared light emitter or other conventional heating devices.
It is also possible to work at room temperature.
In general, before carrying out the rinsing operation or applying the oxidizing composition, the hair on which the reducing composition has been applied is left for a few minutes, generally between 2 and 30 minutes and preferably between 5 and 20 minutes, so as to give the reducing agent enough time to act correctly on the hair. During this waiting period, bonnets can be used for this purpose.
After the optional rinsing operation, a fixing composition containing an oxidizing agent is applied to the hair. These are compositions usually used in processes for permanently reshaping the hair. Oxidizing agents which can be used are peroxides such as aqueous hydrogen peroxide solution or, optionally, urea peroxides, bromates such as alkali metal bromates, persalts or a mixture of alkali metal bromates and a persalt.
The concentration of aqueous hydrogen peroxide solution can range from 1 to 10 volumes, but is preferably of the order of 8 volumes.
The concentration of alkali metal bromates is from 1 to 12% and that of persalts is from 0.1 to 15% by weight relative to the total weight of the oxidizing composition.
The pH of the oxidizing composition can range between 2 and 9 and is preferably between 3 and 8.
The aqueous hydrogen peroxide solution can be stabilized, for example with phenacetin, acetaniline, mono- and trisodium phosphates or with 8-hydroxyquinoline sulphates.
The fixing or oxidizing compositions can also contain basifying or acidifying agents or preserving agents, sequestering agents, opacifiers and treating agents as defined above for the reducing composition.
The mechanical means which kept the hair under tension can be removed from the hair before or after the fixing step.
In any case, after an exposure time of from 5 to 30 minutes, in particular from 5 to 15 minutes, the hair thus treated with the fixing or oxidizing composition is rinsed thoroughly with water.
The examples which follow are intended to illustrate the invention without being limiting in nature.